host alternation of spruce broom rust. | repeated inoculations demonstrate that peridermium coloradense a. & k. is the gametophytic stage of chrysomyxa arctostaphyli diet., previous reports notwithstanding. thus c. arctostaphyli is eliminated as the only familiar exception to transhel's law, which may apply universally to microcyclic rusts. | 1961 | 17834889 |